Navigation system



FIG. 1 illustrates a front elevational view thereof.

FIG. 2 illustrates a rear elevational view thereof.

FIG. 3 illustrates a right side elevational view.

FIG. 4 illustrates a left side elevational view thereof; and,

FIG. 5 illustrates a top plan view thereof. 

The ornamental design for a navigation system, as shown and described herein. 